a. Field of the Invention
The present invention relates to an apparatus for coloring and decoloring sample carriers in electrophoretic systems.
b. Description of the Prior Art
The electrophoresis technique is used for measuring proteins contained in blood serum for clinical inspections in medical institutes. This analysis is carried out, as already known to those skilled in the art, by applying blood serum to be analysed onto a sample carrier made, for example, of cellulose acetate paper or the similar material and electrically energizing the sample carrier to develop fractionated patterns of the blood serum, whereafter the electrically energized sample carrier is colored with a coloring liquid agent and, after the areas other than the blood serum are decolored, the sample is measured with a colorimeter for quantitative determination. Conventionally, various processes of this analysis were manually carried out with low efficiency. Further, analysis by electrophoresis required highly delicate skill and the conventional electrophoretic system had a defect that analytical results were different depending on individual analysts' measuring skills. In view of such circumstances, it has been attempted to develop automatic electrophoretic systems which can automatically carry out the processes of electrophoresis for the purpose of enhancing measuring efficiency and eliminating analytical variations due to difference in measuring skills depending on individual analysts. In order to carry out the coloring and decoloring steps out of the various area in the automatic electrophoretic systems thus developed, such an apparatus as is illustrated in FIG. 1 and FIG. 2 has been designed for coloring, decoloring and drying sample carriers. This conventional coloring-decoloring-drying apparatus will be described below:
In FIG. 1 and FIG. 2, the reference numeral 1 represents a casing which is mounted on a stand designated by the reference numeral 2. The reference numerals 3 and 4 denote rollers respectively which are attached to mounting brackets 5 and 6 in the vicinity of entrance 1a of the casing 1. The reference numerals 7 and 8 represent a light emitting diode and an optical detector element respectively which are arranged over and under the entrance 1a so as to provide a system for detecting a sample carrier. The reference numeral 9 denotes a bonding drum which is rotatably arranged in the casing 1 in a manner described later and has a central concave section 9a which is lower than both side edges 9b along the circumferential surface as shown in FIG. 2. Fixed to both the side edges 9b and portion of the concave section 9a of the bonding drum 9 are members 9d and 9e which are made of sponge or the similar material and are to be used for bonding a sample carrier. The reference numerals 10 and 11 represent rollers which are attached to a support plate 12 respectively. Of these rollers, the roller 10 is always kept in contact with the bonding drum by an adequate means such as a spring which pulls said roller toward the center of the bonding drum. The reference numeral 13 represents a sample carrier guide which is attached to the support plate 12. The reference numerals 14, 15 and 16 designate rollers respectively and the reference numeral 17 denotes a carrier support guide. These rollers and carrier guide are quite the same as those described above. Now the mechanism for rotating the bonding drum will be described with reference to FIG. 2.
The reference numeral 20 represents a first motor, the reference numerals 21 and 22 designate gears respectively and the reference numeral 23 denotes a one-way clutch which functions to transmit rotation of the gear 22 to the shaft 9c of the drum only when the gear rotates, for example, clockwise as seen from the right side of the figure. The reference numeral 25 represents a second motor. The reference numerals 26 and 27 designate gears respectively and the reference numeral 28 denotes a shaft to which the gear 27 is fixed and whose one end is fixed to the support plate 12. The reference numeral 29 represents a one-way clutch which transmits rotation of the gear to the shaft 9c of the bonding drum only when the gear rotates counterclockwise as seen from the left side of the figure. The reference numeral 30 represents a trough containing, for example, a coloring liquid agent and is movable up and down by an adequate hoist means through an opening 2a formed in the stand 2 in such a manner that the trough is hoisted up from the position shown in the figure into the casing 1 through the opening 2a until the lower portion of the bonding drum 9 is dipped into the coloring liquid agent 31. Further, the reference numeral 32 used in FIG. 2 represents a duct which has the other end (not shown) connected to a drying air blower and through which dry air is to be blown for drying the sample carrier.
Now, operations of the conventional coloring-decoloring-drying apparatus will be described below. First, a sample carrier with fractionated patterns formed by applying blood serum onto the sample carrier made of cellulose acetate paper or the similar material and electrically energizing it is inserted through the entrance 1a. In the coloring-decoloring-drying apparatus, the insertion of the sample carrier is detected with a carrier detecting system consisting of the light emitting diode 7 and optical detector element 8, and the bonding drum 9 is rotated. Speaking more detailedly, the first motor 20 shown in FIG. 2 starts to rotate the bonding drum 9. In this case, the first motor 20 is rotated in such a direction as to turn the gear 22 clockwise as seen from the right side of FIG. 2 so that rotation of the gear 22 is transmitted to the shaft 9c which in turn rotates the bonding drum 9. By this rotation, the sample carrier is fed to the surface of the bonding drum 9 and adheres onto the circumference thereof, whereafter said sample carrier is finally held in a condition bonded to the member 9d made of sponge or the similar material of the bonding drum 9. In this step, the starting position of the bonding drum 9 is set in such a manner that the member 9e fixed to said drum will just meet the leading end of the sample carrier when it just reaches the surface of the bonding drum 9. Therefore, the leading end of the sample carrier first adheres to the member 9e and the sample carrier is fed while gradually adhering to the member 9d which is fixed on both the sides of the bonding drum 9. Further, the length of the surface of the bonding drum 9 as measured from the roller 10 to the roller 14 is selected so as to be a little shorter than the length of the sample carrier and the rotation of the bonding drum 9 is stopped after the sample carrier adheres onto the bonding drum 9, and the leading end of the sample carrier is inserted between the bonding drum 9 and the roller 14. Hence, both the ends of the sample carrier are caught between the bonding drum 9 and rollers 10 and 14 respectively, whereby the sample carrier is held in a condition adhering to the bonding drum 9. In this condition, the second motor 25 starts rotating. In this step, the second motor 25 is rotated in such a direction as to turn the gear counterclockwise as seen from the left side of FIG. 2. Hence, the shaft 28 which is fixed to the gear 27 rotates also in the same direction and the shaft 9c of the bonding drum 9 is rotated through the one-way clutch 29. Accordingly, the support plate 12 which is fixed to the shaft 28 is turned together with the bonding drum 9. Therefore, the sample carrier is rotated as a whole with both its ends held between the bonding drum 9 and the rollers 10 and 14 respectively. When the bonding drum 9 makes half a turn to place the sample carrier at its lowermost position, the motor 25 stops operating. In this condition, the bonding drum 9, support plate 12, roller 10, etc. are kept stationary at the positions just vertically inverted from those shown in the figure. With the members kept in these positions respectively, the coloring liquid trough 30 is hoisted up until the lower portion of the bonding drum 30 is dipped into the coloring liquid agent 31. Therefore, the sample carrier fixed to the bonding drum 9 is also dipped into the coloring liquid agent. The sample carrier is maintained in this position for a definite time to be colored with the liquid agent. After the sample carrier has been colored, the coloring liquid trough 30 is hoisted down and a decoloring liquid trough (not shown) having the same construction as that of the coloring liquid trough is inserted instead through the opening 2a of the stand 2, whereby the colored sample carrier is dipped into a decoloring liquid agent and decolored in the area other than the blood serum. After the sample carrier has been decolored in this way, the decoloring liquid trough is shifted out of the casing 1 and warm air is blown into the casing 1 to dry the sample carrier. After the sample carrier has been colored, decolored and dried, the motor 25 is rotated again to turn the bonding drum 9, support plate 12, rollers 10 and 14, etc. as a whole in the manner already described above. When these members are returned to their initial positions respectively, the second motor 25 is stopped and the first motor 20 is rotated to turn the bonding drum 9 together with the sample carrier. In this case, however, the tip of the guide plate 17 which is a little protruding inside the bonding drum 9 serves to peel off the sample carrier from the surface of the bonding drum, whereby the sample carrier passes between the roller 14 and guide plate 17, and is sent to the next stage through the exit 1b of the casing 1. On the conventional coloring-decoloring-drying device described above, the sample carrier is elongated while it is soaked with the coloring liquid agent or decoloring liquid agent, but contracts after are dried. Since both the ends of the sample carrier is fixed between the drum and the rollers respectively, the sample carrier is often deformed or torn after it is dried. The conventional coloring-decoloring-drying apparatus had such a defect.
Further, the conventional apparatus had another defect that it is designed unavoidably as a large unit since it functions to bond the sample carrier onto the bonding drum 9 accommodated in the casing 1 and to dip the sample carrier into liquid agent by hoisting up the coloring or decoloring liquid trough into the casing 1 from outside said casing.